ROT13 Cipher
Encode or decode text with the classic ROT13 letter-substitution cipher.
This tool runs entirely in your browser. Your files are never uploaded to a server.
ROT13 is its own inverse — run the output back through this tool to get your original text.
Type or paste any text and watch it transform live using ROT13, the simple cipher that shifts each letter 13 places through the alphabet. Because ROT13 is its own inverse, running the result through the tool again gives you back the original text — one box, no encode/decode toggle needed. Everything happens locally in your browser, so nothing you type ever leaves your device.
Frequently Asked Questions
- How does ROT13 work?
- ROT13 shifts every letter 13 positions forward in the alphabet, wrapping around at the end. Numbers and symbols are left untouched.
- Why is there no separate 'decode' button?
- ROT13 is symmetric: applying it twice returns the original text, so the same box works for both encoding and decoding — just paste the output back in.
- Is ROT13 secure for hiding sensitive data?
- No — ROT13 is not encryption and offers no real security. It's meant for obfuscating text like spoilers or puzzle answers, not protecting sensitive information.